BACI provides bilateral export values (in thousand of US dollars) and quantities (in tons) at the 6-digit level of Harmonized System, for more than 254 countries since 1989. Original data come from the United Nations Statistical Division (COMTRADE database). This source database provides the declarations of the exporter and the importer, that gives double information for each flow (exporter-importer-product-year).

BACI is constructed using an original procedure that reconciles the declarations. This harmonization procedure enables to extend considerably the number of countries for which trade data are available, as compared to the original dataset. First, as import values are reported CIF (cost, insurance and freight) while exports are reported FOB (free on board), insurance and freight costs are estimated and removed from imports values to compute all flows free on board. Second, the reliability of country reporting is assessed based on the reporting distances among partners. These reporting qualities are used as weights in the reconciliation of each bilateral trade flow twice reported (see Gaulier & Zignago, 2010).
BACI on CEPII website: http://www.cepii.fr/CEPII/fr/bdd_modele/presentation.asp?id=1